With a budget of £300 I think you would be better of going for AMD. In my own opinion Intel makes a better processor, but for budget AMD is best. Getting an AMD processor will enable you to getter better components for the rest of the system and the Athlon is a good processor. Whether it should be 64bit depends on how future proof you want your system to be. There are currenntly no programs (or very few) designed for 64bit, and for 32bit applications they actually run slower than 32bit processors.